safeway. ingredients for life. ♪ you are the one i want ♪ you are the one i want ♪ woo, woo, woo honey ♪ >>> the best-selling duet in pop music history. high above times square. a great crowd down below. and olivia newton-john and john travolta, back together again. they are here on "gma," this morning, after 30 years. we're going to hear some of the new songs, hear about their new causes. and what really happened behind the scenes of "grease." we say good morning, america. and elizabeth. so much of our hearts and minds still on newtown. >> absolutely. and a lot of people are wondering, after adam lanza committed this horrific crime what we can do in this country to help our young people. there's an estimated one in five children that suffer from mental illness in this country. and many do not get help, mostly because parents can't find the help. we're going to get into that segment this morning, on what parents should look for. and how to get the much-needed resources. >>> and then, w